DHA reduces intracellular PTEN levels in cortex after cervical hemisection. A, B, Low-magnification images of the cerebral cortex labeled for PTEN immunoreactivity in cervical lateral hemisected rats at 1 d after injury. C–F, Higher magnification of the dashed boxes in A, B showing that PTEN immunoreactivity is colocalized with NeuN-immunopositive neurons in the cerebral cortex. DHA-treated animals have reduced PTEN immunostaining compared with vehicle-treated animals. G, J, A low expression of PTEN immunoreactivity was observed in the cortex of naive and sham animals. K, Quantitative analysis revealed a significant increase in PTEN immunostaining in the cerebral cortex ipsilateral to the lesion side at 1 d after cervical SCI in the vehicle group. DHA treatment (red bar) significantly reduces the PTEN immunostaining levels compared with the vehicle treatment (blue bar). *p < 0.05. Scale bars: A, B, 200 μm; C–J, 100 μm.